Waste Generation and Waste Disposal CHAPTER 16
Paper or Plastic? Polystyrene plastic polymer with high insulation value Aka styrofoam Is harmful to environment In response to public sentiment Switch to paper cup but is this really better? Use cradle-to-grave or life-cycle analysis:
Paper or Plastic Paper Cup 2 grams petroleum 33 grams wood/bark (R) More E (2x) and water used Heavier more transportation cost/fossil fuels used More air pollution from fossil fuels Only used once Can be recycled/composted If put in landfill will decompose faster Less health risk? 3 grams petroleum No wood/bark Plastic Cup Less energy and water used Lighter less transportation cost/fossil fuels used Less air pollution from fossil fuels Can be used more than once Landfill long time to decompose More health risk? Bleach by-product can damage aquatic life --------------------------------- Little energy from incineration Little energy from incineration
Humans generate waste that other organisms cannot use Inputs plant materials, nutrients, water, energy Outputs waste Anything not useful or consumed and nonuseful products
Municipal Solid Waste We live in a throw-away society Planned obsolescence Municipal solid waste - refuse collected by municipalities from households, small businesses, and institutions such as schools, prisons, municipal buildings and hospitals Varies by season of year, socioeconomic status of the individual generating the waste and geographic location within the country Some stats:
Content of the Solid Waste Stream Waste stream the flow of solid waste that is recycled, incinerated, placed in a solid waste landfill, or disposed of in another way
Composition of Municipal Solid Waste another analysis 31% - paper 33%- organic materials (yard waste, food scraps, wood) 12%- plastic 18%- durable goods (appliances, tires)
E-Waste Electronic waste (E-waste) - televisions, computers, cell phones that contain toxic metals Increasing rapidly Great environmental effect Little incentive to recycle Voluntary programs Concern costs more to recycle US exports e-waste to China
Reduce, Reuse, Recycle Reduce- waste minimization or prevention Source reduction seeks to reduce waste by reducing the use of materials destined to become MSW Other benefits: Packaging is concern Substitution Reuse- reusing something like a disposable cup more than once May involve repairing an existing object Agents of reuse Recycle- next slide
The 3 rd R Closed loop recycling vs. open-loop In US - increased since 1975 Zero-sort recycling programs Benefits Requires more energy than reduce and reuse Goal of Recycling?
Composting Organic material (ie. food and yard waste) cause problems in landfills: Compost- organic material that has decomposed under controlled conditions to produce an organic-rich material Compostable material includes Meat/dairy usually not composted Composting tips: Simple vs. sophisticated C:N ratio of 30:1 Turn over compost regularly
Landfills Open dumps still common in developing world Problems Sanitary landfills- engineered ground facilities designed to hold MSW with as little contamination of the surrounding environment as possible Leachate- the water that leaches through the solid waste and removes various chemical compounds with which it comes into contact
Sanitary Landfill
Sanitary Landfills Costs: Building landfill is very expensive Tipping fee Choosing a site for sanitary landfill: Some requirements: Siting is often controversial and can be politically charged Some problems with landfills:
Incineration Incineration- the process of burning waste materials to reduce its volume and mass and sometimes to generate electricity and heat Ash residual nonorganic material that does not combust during incineration Bottom ash Fly ash Pollutants released included
How does incineration work?
Incineration Waste-to-energy when heat generated by incineration is used rather than released in the atmosphere
Hazardous Waste Hazardous waste- liquid, solid, gaseous, or sludge waste material that is harmful to humans or ecosystems Collection sites - must be staffed with specially trained personnel Periodic collection held Once collected - sorted into a number of categories Hazardous waste must be treated before disposal
Laws Resource Conservation and Recovery Act (RCRA) - designed to protect human health and the natural environment by reducing or eliminating hazardous waste Also know as cradle-to-grave tracking RCRA ensures that hazardous waste is tracked and properly disposed of 1984 Hazardous and Solid Waste Amendments (HSWA)
Laws Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Also know as Superfund Puts a tax on the chemical and petroleum industries This revenue is used to cleanup Requires the federal government to respond directly to the release of substance that may pose a threat to human health or the environment Problems:
Superfund Sites in US
Brownfields Contaminated industrial or commercial sites that may require environmental cleanup before they can be redeveloped or expanded Includes: old factories, industrial areas and waterfronts, dry cleaners, gas stations, landfills, and rail yards Critics: inadequate solution to contaminated locations in country
International Consequences Municipalities and industries may send waste to countries with less stringent regulations Examples: Tugboat Break of Dawn (from NY in 1987) Khian Sea (a Bahamian ship hired by Philly in 1986) Mercury from India to PA
Life Cycle Analysis Looks at the materials used and released throughout the lifetime of a product Life Cycle Analysis
Alternative Ways to Handle Waste Integrated Waste Management A method that seeks to develop as many options as possible, to reduce environmental harm and cost Utilizes reduction, recycling, composting, landfills, and incineration No single method works for everyone